Continuing progress toward the completion of mapping the chromomere patterns of the entire chromosome complement at the pachytene stage of meiosis in human males requires the collection of additional data by use of light microscopy. These data will allow us to document the sequencing of chromomeres of various sizes in further autosomal bivalents, and thereby to construct provisional maps. The extent of variability evident in our specimens will be examined and if significant structural variation is found, correlations with phenotypic expression will be sought. Certain homologies with metaphase banding patterns are now evident, and these will be defined wherever possible.